update installation insturctions

Author: DocOtak

docs/installation.rst

@@ -3,11 +3,11 @@ Installation
 
 Python Requirements
 -------------------
-This package is tested on python 3.6 through 3.9 on a linux environment, it has been run in a macOS environment and should also work on Windows.
+This package is tested on python 3.10 through 3.12 on a linux environment, it has been run in a macOS environment and should also work on Windows.
 
 Install With pip
 ----------------
-Installation in your preferred python 3.6~3.9 environment should be as simple as:
+Installation in your preferred python 3.10~3.12 environment should be as simple as:
 
 .. code-block:: console
     
@@ -23,19 +23,6 @@ The current dependencies are:
 * click>=7.0.0
 * appdirs>=1.4.0
 
-Optional Dependencies
----------------------
-When using this library in a `Google Colab <https://colab.research.google.com/>`_ environment, getting the api key to the right place can be tricky.
-For this reason, there is an optional dependency on:
-
-* colab_env>=0.2.0
-
-This can be automatically installed for you using the extras syntax when installing:
-
-.. code-block:: console
-
-    pip install 'cchdo.auth[colab]'
-
 Installation in an IPython Env (like colab)
 -------------------------------------------
 This can be installed in a Jupyter/IPython/Google Colab environment by using the "Shell execute" `magic command <https://ipython.readthedocs.io/en/stable/interactive/magics.html>`_.
@@ -45,11 +32,5 @@ Simply run this in an empty cell in the notebook:
 
     !pip install cchdo.auth
 
-If you are in Google Colab, include the ``colab`` extra:
-
-.. code-block:: console
-
-    !pip install 'cchdo.auth[colab]'
-
 .. note::
     The ``!`` prefixing the pip command is required in a Jupyter/IPython/Google Colab cell.